[Bug target/47025] Dead stores in variadic functions not eliminated

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47025

--- Comment #5 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-09-06 
15:56:26 UTC ---
Author: rguenth
Date: Tue Sep  6 15:56:20 2011
New Revision: 178601

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=178601
Log:
2011-09-06  Richard Guenther  <rguent...@suse.de>

    PR tree-optimization/47025
    * tree-ssa-alias.c (ref_maybe_used_by_call_p_1): BUILT_IN_VA_END
    uses nothing.
    (call_may_clobber_ref_p_1): BUILT_IN_VA_END is a barrier like
    BUILT_IN_FREE.
    (stmt_kills_ref_p_1): BUILT_IN_VA_END kills what its argument
    definitely points to.
    * tree-ssa-structalias.c (find_func_aliases_for_builtin_call):
    BUILT_IN_VA_START doesn't let its va_list argument escape.
    * tree-ssa-dce.c (propagate_necessity): BUILT_IN_VA_END does
    not make any previous stores necessary.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/tree-ssa-alias.c
    trunk/gcc/tree-ssa-dce.c
    trunk/gcc/tree-ssa-structalias.c